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Biomedical subjects

Yoshihiro Maegaki

Publications and source records attributed to Yoshihiro Maegaki.

At least 19 recordsLinked to original sources

Serial diffusion-weighted MRI in hemorrhagic shock and encephalopathy syndrome.

This report presents a case of hemorrhagic shock and encephalopathy syndrome. In the acute stage, brain magnetic resonance imaging demonstrated symmetrical hyperintensity on diffusion-weighted images and hypointensity on the apparent diffusion coefficient maps in the subcortical white matter. Whereas the abnormal diffusion-weighted imaging signals of the white matter resolved in the subacute stage, the adjacent gray matter became hyperintense on diffusion-weighted images and hypointense on apparent diffusion coefficient maps. The evolution of diffusion-weighted imaging signals is thus considered to be one of the early findings in hemorrhagic shock and encephalopathy syndrome.

Brain↗

A patient with simplified gyral pattern followed by progressive brain atrophy.

We present the case of a three-year-old boy who suffered from intractable epilepsy from birth, and who displayed microcephaly and severe developmental delay. Neuroradiological examination revealed the presence of simplified gyri of the cerebral cortex, and increased signal intensity changes in the cerebral white matter on T2-weighted magnetic resonance imaging. A tentative diagnosis of congenital cortical malformation was made, but unexpectedly, the cerebrum, cerebellum, and pons showed a progressive atrophy during the follow-up period. The basal ganglia and thalamus were relatively spared. Investigations could find no evidence of leukodystrophies, metabolic disorders, hereditary brain anomalies, or congenital central nervous infections. This case may represent a novel type of neurodegenerative disease with malformation of cortical development.

Atrophy↗

Disappearance of frontal N30 component of median nerve stimulated SSEPs in two young children with abnormal striatal lesions.

Median nerve stimulated short-latency somatosensory evoked potentials (MN-SSEPs) were performed in two young children with extrapyramidal symptoms. Brain MRI showed bilaterally symmetric striatal lesions in both cases. The subcortical components (N9, N11, N13, N18, P11, and P13) and the parietal component (N20) were normally detected, whereas the frontal component (N30) was not detected bilaterally in either case. In conclusion, our findings suggest that frontal N30 disappearance could be observed since as early as young childhood and it may pathophysiologically reflect severe dysfunction in the extrapyramidal system.

Brain Injuries↗

Facioscapulohumeral muscular dystrophy with severe mental retardation and epilepsy.

We report here a case of a 20-year-old woman with facioscapulohumeral muscular dystrophy (FSHD). In this patient, the involvement of facial muscle had been present since early childhood, but obscured due to the complication of profound mental retardation. Epilepsy emerged at eight years of age. Symmetrical limb muscle weakness appeared at 15 years of age, which progressed such that she was wheelchair-bound at 18 years of age. An elevated serum creatine kinase, predominant involvement of hamstrings, scapular and abdominal muscles, as well as an impaired stapedial reflex at high tune, were compatible with the clinical features of FSHD. The diagnosis of 4q35-FSHD was confirmed by detection of a 10kb EcoRI fragment with a p13E-11 probe on a Southern blot. The intellectual disability in this patient was the most severe of all FSHD patients reported to date and has hindered a correct diagnosis. This entity should be included in the differential diagnoses for patients with muscular symptoms and accompanying mental retardation.

Adult↗

Delayed neuropsychiatric syndrome in a child following carbon monoxide poisoning.

Here, we report the case of a five-year-old boy with carbonic monoxide (CO) poisoning. The patient initially recovered after the initiation of hyperbaric oxygen (HBO) therapy, but lethargy as well as visual and gait disturbances appeared two days later. Left hemiparesis and mood lability also subsequently appeared. Slow frontal activity was noted on electroencephalography, while fluid-attenuation inversion recovery and diffusion-weighted magnetic resonance imaging (MRI) revealed high signal-intensity lesions in the hippocampus and deeper layers of the occipital and frontal cerebral cortex. The neurological symptoms subsided gradually during the 10-day course of HBO therapy, but the left-hand paresis and quadrantic hemianopsia persisted, in association with impaired attention, slow mental processing, and incontinence. Lesions in the globus pallidum were noted on follow-up MRI at 14 days, and cortical lesions became evident as linear, low signal-intensity areas on T1-weighted imaging 4 months after presentation. Delayed neuropsychiatric syndrome in CO poisoning is rare in childhood, although children should be carefully monitored after CO exposure. The finding of cortical laminar necrosis in this patient is quite atypical in CO poisoning, and suggests a broader and previously nonpredicted pathomechanism in this condition.

Carbon Monoxide Poisoning↗

Acute encephalitis with refractory, repetitive partial seizures: case reports of this unusual post-encephalitic epilepsy.

We report on three acute encephalitis patients with refractory, repetitive partial seizures (AERRPS). All three suffered acute febrile episodes associated with status epilepticus, which necessitated high-dose barbiturate therapy under artificial ventilation for several weeks. Electroencephalography (EEG) revealed a predominance of diffuse epileptiform discharges initially, subsequently developing into periodic bursts of these discharges. Reduction of the barbiturate dosage resulted in clinical and subclinical partial seizures appearing repetitively in clusters. Prolonged fever persisted for 2-3 months, even several weeks after normalization of cell counts in the cerebrospinal fluid. The EEG showed an improvement after resolution of this fever, and seizures became less frequent, although still intractable. Oral administration of high-dose barbiturate and benzodiazepines were partially effective during the acute phase, and a barbiturate dependency, lasting for years, was noted in one patient. Steroid administration was effective in stopping the febrile episodes in one patient, with concurrent improvement in seizure control. Magnetic resonance imaging showed enhancement of bitemporal cortical areas in one patient, and high signal intensity on T2 weighted image in the bilateral claustrum in another patient. Diffuse cortical atrophy appeared within two months after the onset of encephalitis in all patients. The evolution of the seizures and EEG findings suggested a high degree of cortical excitability in AERRPS. In this report, we propose a tentative therapeutic regimen for seizure control in this condition. We also hypothesize that a prolonged inflammatory process exists in the cerebral cortex with AERRPS, and may be pivotal in the epileptogenesis.

Acute Disease↗

Lower brainstem dysfunction in an infant with persistent primitive trigeminal artery.

A 6-month-old boy with persistent primitive trigeminal artery (PPTA) presented with stridor, dysphagia, delayed motor development and postural neck and shoulder dystonia. Magnetic resonance imaging/angiography and ultrasonography revealed PPTA, with flow from the dilated basilar artery to the right internal carotid artery, lower brainstem compression by the dilated basilar artery, and cerebellar vermis hypoplasia. Evoked potentials showed lower pons and medulla oblongata functional disruption. These lesions may be related to vascular etiology in the lower brainstem or to congenital malformation syndrome involving infratentorial structures. The relationship of this condition to Möbius syndrome is discussed.

Abnormalities, Multiple↗

Topographic MN-SSEPs (N18, N20 and N30) might characterize underlying CNS involvements in representative types of cerebral palsy.

This study is aimed at constructing the neurophysiological basis for determining the characteristic features of cerebral motor disturbance in representative cerebral palsy (CP) types using topographical S-SEPs technology. Median-nerve stimulated S-SEPs (MN-SSEPs) were examined for 23 patients with four representative types of cerebral palsy: 6 athetotic (including 3 patients due to hypoxic-ischemic encephalopathy (HIE) and 3 to kernicterus), 7 hemiplegic, 5 diplegic and 5 tetraplegic types, and 13 normal controls. In HIE group of athetotic CP, frontal N30 specifically showed severe amplitude reduction or abolishment. In hemiplegic CP, both N20 and N30 on the affected cerebral side tended either to disappear or to be normally evoked at the same time, and their mean amplitudes declined severely. In diplegic CP, the amplitudes of subcortical N18 and parietal N20 were not small but significantly enlarged. N30 amplitude stayed within normal. The reason for this unexpected enlargement of N18 and N20 is unclear, but may be partly due to premature birth which caused abnormally abundant dendritic spine due to absence from perinatal normal spine elimination in the brainstem. In several quadriplegic patients, both N20 and N30 disappeared. The mean amplitude of N30 severely decreased. In conclusion, topographical results of N18, N20 and N30 may basically suggest the underlying involvement of nervous structures in CP according to their representative type.

Adolescent↗

Monozygotic twins discordant for Klippel-Feil syndrome.

In a pair of Japanese monozygotic twins, one manifested Klippel-Feil syndrome, a short neck with C(1-4) vertebra fusion, whereas the other was normal. The discordance between the twins suggests that Klippel-Feil syndrome results in part from a postzygotic somatic mutation or intrauterine environmental factors.

Diseases in Twins↗

[Polycystic ovary syndrome and hepatocellular adenoma related to long-term use of sodium valproate in a young woman].

Previous studies have reported a high prevalence of polycystic ovary syndrome (PCOS) among women taking sodium valproate (VPA). We report the case of a 28 year-old epileptic female taking VPA, who developed PCOS and later hepatocellular adenoma. She had been taking VPA for intractable epilepsy since the age of 15 months. At the age of 22 years, she suffered spontaneous rupture of a liver tumor that was diagnosed as hepatocellular adenoma. At the age of 24 years, bilateral polycystic ovaries were found by transabdominal ultrasonography, and PCOS was diagnosed. VPA may directly influence steroidogenesis in the ovary and cause hyperandrogenemia with ensuing PCOS. It is known that abnormality in the sex hormones contributes to the onset of hepatocellular adenoma. Therefore, we speculate that hyperandrogenemia due to VPA contributed to the development of hepatocellular adenoma in this case.

Adenoma, Liver Cell↗

[Pulmonary atelectasis in patients with neurological or muscular disease; gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position].

We report 10 cases of pulmonary atelectasis diagnosed by chest computed tomography in patients with neurological or muscular disease. Atelectasis was frequently seen in hypotonic patients who could not roll over on their own. The atelectases located mostly in the dorsal bronchopulmonary segments, adjacent to the heart or diaphragm. Atelectasis diminished in two patients after they became able to roll themselves over. Gravity-related lung compression by the heart and intra-abdominal organs on persistent supine position can cause pulmonary atelectasis in patients with neurological or muscular disease who can not roll over by their own power. To confirm that the prone position reduces compression of the lungs, chest computed tomography was performed in both the supine and the prone position in three patients. Sagittal images with three-dimensional computed tomographic reconstruction revealed significant sternad displacements of the heart and caudal displacements of the dorsal portion of the diaphragm on prone position compared with supine position. The prone position, motor exercises for rolling over, and biphasic cuirass ventilation are effective in reducing gravity-related lung compression. Some patients with intellectual disabilities were also able to cooperate in chest physiotherapy. Chest physiotherapy is useful in preventing atelectasis in patients with neurological or muscular disease.

Abdomen↗

[Influenza-associated encephalopathy with onset of prolonged convulsion: a case report].

A 1-year-old girl with influenza-associated encephalopathy initially exhibited prolonged febrile convulsions and subsequent drowsiness. She became unconsciousness and experienced a cluster of seizures 4 days later. Diffusion-weighted magnetic resonance imaging (DWI) showed high signal intensity in the bilateral frontal white matter. This signal change migrated to the bifrontal cortical areas and the caudate nuclei within 10 days, when T2 elongation appeared over the gray and white matter of frontal lobes. Choreoathetosis and oculogyric crisis were transiently noted at this period. Frontal lobe signs, including the forded mouth opening response, after diminution of these movement disorders. The DWI signal change subsequently resolved and frontal cortical atrophy appeared thereafter. Levels of inflammatory cytokines in the cerebrospinal fluid were normal during the acute phase of clinical course. The biphasic clinical course with initial prolonged seizure, involvement of the frontal lobes, and the progression of signal change on DWI from white to gray matter, meets the characteristics of "status epilepticus-type acute encephalopathy" suggested by Shiomi et al. Although pentobarbital infusion, steroid pulse therapy and mild hypothermia did not show any apparent effects on the clinical course of this patient, further trial of these therapies may be warranted for the treatment of this type of encephalopathy.

Diffusion Magnetic Resonance Imaging↗

Forced mouth opening reaction: a primitive reflex released from cortical inhibition.

We report the case of a 6-year-old girl with congenital adrenal hyperplasia, who showed 'forced mouth opening reaction' during the course of acute encephalopathy due to adrenal crisis. When an object was moved towards her mouth, or when the corner of her mouth was stroked with a tongue depressor, she would immediately open her mouth fully and hold it open. This reaction appeared transiently during the course of her illness in association with other frontal release signs including the rooting, groping and palmomental reflexes. Magnetic resonance imaging showed bilateral widespread lesions involving the gray and white matters in the frontal lobes, and less severe lesions in the temporal and parietal areas. We propose that this unique reaction is a sign of a release phenomenon, and represents the emergence of primitive reflexes in the absence of cortical inhibition in some types of encephalopathies.

Acidosis↗

EEG evaluation of fixation-off sensitivity in eyelid myoclonia with absences.

A 14-year-old female of moderately retarded intelligence exhibited frequent seizures of eyelid myoclonia with absences. Video-electroencephalographic recording revealed that slow eye closure was followed by eyelid myoclonia with absence seizures and that paroxysmal burst activities in the occipital region always preceded generalized spike-wave discharges. Paroxysmal burst activities were induced not only by slow eye closure but also by fixation-off, wearing Frenzel glasses. We speculate that the sensitivity to fixation-off in the occipital lobe is one of the triggering mechanisms in eyelid myoclonia with absences.

Adolescent↗

Approximate entropy in the electroencephalogram during wake and sleep.

Entropy measurement can discriminate among complex systems, including deterministic, stochastic and composite systems. We evaluated the changes of approximate entropy (ApEn) in signals of the electroencephalogram (EEG) during sleep. EEG signals were recorded from eight healthy volunteers during nightly sleep. We estimated the values of ApEn in EEG signals in each sleep stage. The ApEn values for EEG signals (mean +/- SD) were 0.896 +/- 0.264 during eyes-closed waking state, 0.738 +/- 0.089 during Stage I, 0.615 +/- 0.107 during Stage II, 0.487 +/- 0.101 during Stage II, 0.397 +/- 0.078 during Stage IV and 0.789 +/- 0.182 during REM sleep. The ApEn values were found to differ with statistical significance among the six different stages of consciousness (ANOVA, p<0.001). ApEn of EEG was statistically significantly lower during Stage IV and higher during wake and REM sleep. We conclude that ApEn measurement can be useful to estimate sleep stages and the complexity in brain activity.

Adult↗

Approximate entropy of the electroencephalogram in healthy awake subjects and absence epilepsy patients.

The approximate entropy (ApEn) of signals in the electroencephalogram (EEG) was evaluated in 8 healthy volunteers and in 10 patients with absence epilepsy, both during seizure-free and seizure intervals. We estimated the nonlinearity of each 3-sec EEG segment using surrogate data methods. The mean (+/- SD) ApEn in EEG was 0.83 +/- 0.22 in healthy subjects awake with eyes closed. It was significantly lower during epileptic seizures (0.48 +/- 0.05) than during seizure-free intervals (0.80 +/- 0.13) (P < 0.001). Nonlinearity was clearly detected in EEG signals from epileptic patients during seizures but not during seizure-free intervals or in EEG signals from healthy subjects. The ApEn of EEG signals estimated over consecutive intervals could serve to determine pathological brain activity such as that occurring during absence epilepsy.

Adult↗

[No association between moyamoya disease and polymorphism of IGF2R].

Moyamoya disease is a cerebrovascular disorder of unknown etiology. Its high incidence in East Asia and accumulation in family members suggest a genetic background. A high incidence of maternal inheritance implicates genomic imprinting in this disorder. Based on this hypothesis, we studied the association between moyamoya disease and IGF2R gene on chromosome 6, but found no evidence for such association between them. On the other hand, heterogeneous expressions of IGF2R were confirmed in the lymphocytes. Some individuals showed monoallelic expression and others showed biallelic expression.

Adult↗

[Molecular screening for moyamoya disease by use of expressed sequence tag on chromosome 3p].

Moyamoya disease is a well-known cerebrovascular disorder of unknown pathogenesis affecting terminal portion of internal carotid arteries and causing ischemic attacks. Its familial occurrence suggests genetic background. We hypothesized that paternally imprinted gene might be associated with this disorder. To identify the expressed sequence tags (ESTs) with monoallelic expressions on chromosome 3, we used mouse A9 hybrid cells having human chromosome 3. Two ESTs showed only maternal expression in mouse A9 hybrid cells, and four showed non-expression in the lymphocytes derived from moyamoya patients. Although these ESTs are clustered on the same 150 kb region, we finally failed to identify cDNA in this region.

Adult↗